Each field can hold only one type of bean so if you must plant a type of bean that's not in one of your fields then you must harvest a field to make room for the new arrival.
On a turn you must plant the first one or two cards in your hand into the fields in front of you. Unlike in most other cards games you cant rearrange the order of cards in hand so you must use them in the order that you've picked them up from the deck - unless you can trade them to other players which is the heart of the game. Each player starts with a hand of random bean cards and each card has a number on it corresponding to the number of that type of beans in the deck. In Bohnanza you plant then harvest bean cards in order to earn coins.
